I am going to import my current blog posts on to my future to-be self-hosted wp blog. It will take somedays before I make it the primay blog.
In the WP Privacy Settings I have set "Ask search engines not to index this site"

Is this setting enough so as to not affect my current page rankings?

Or do I need to do something else may be messing with robots.txt or anything?

Or are there any side-effects with this settings?

EDIT: It says underneath: "Note: Neither of these options blocks access to your site — it is up to search engines to honor your request."